Nuclear medicine specialists are scrambling to cope with a shortage of isotopes that now seems likely to continue at least through the end of July.

Nuclear medicine specialists are scrambling to cope with a shortage of isotopes that now seems likely to continue at least through July.

Repairs to Canada's National Research Universal facility (NRU) -- begun after leaks were discovered in the reactor vessel last May -- are now projected to take another four months, according to Atomic Energy of Canada Ltd. (AECL), which operates the device.

The delay -- combined with the shutdown of Holland's Petten reactor -- means the world supply of a key isotope is dramatically limited, forcing clinicians to use other techniques.

"It's creating a serious problem for us in terms of our ability to meet the needs of our patients," said Robert Atcher, PhD, of the University of New Mexico, past president of the Society of Nuclear Medicine and chairman of its isotope committee.

Physicians are scrambling to find other ways of diagnosing and treating patients, Atcher told MedPage Today.

Those other methods, however, have drawbacks, including higher cost, lower accuracy, and a greater radiation dose, he said. In some cases, they are also more invasive.

At issue is a shortage of molybdenum-99, a byproduct of nuclear fission. The molybdenum is packed into so-called "generators" which, over about a two-week period, deliver a supply of another radioactive substance, technetium-99m.

The technetium-99m is used in more than 16 million nuclear imaging procedures a year in the U.S. alone, including sentinel node biopsies in cancer surgery, bone scans, and staging cancer patients, among other diagnostic procedures.

For many years, the world supply of molybdenum-99 has come from five reactors -- one each in Canada, Holland, Belgium, France and South Africa. A sixth facility, in Australia, has not yet entered the world market.

The first two facilities aren't producing the isotope now, but radiologists expected that the crunch period with both reactors out of the market would be over in the next few weeks. (See Looming Isotope Shortage Has Clinicians Worried)

Instead, the NRU machine, which produces between up to 40% of the world's supply, is likely to be out of action for several more months. AECL said in a release that eight of 10 necessary welds have been completed, but the remaining two are "particularly challenging," leading to the delay.

Meanwhile, one of the two U.S. companies that makes technetium-99m generators, Covidien, said the FDA and Health Canada have approved Poland's Maria Research Reactor as a site for molybdenum-99 production.

That should help ease the shortage, the company said.

The NRU shutdown is hitting hard for two reasons, Atcher said. First, of course, the machine is responsible for a large share of the supply. Second, it normally has excess capacity and could increase production as a backstop when other reactors are shut for maintenance, he said.

In the long run, Atcher said, the shortage may affect how referring physicians deal with patients who would have been sent for a nuclear medicine test or treatment.

If the technetium-99m generators remain in short supply, he said, doctors may prefer to refer patients for other types of tests -- a CT angiography, for instance -- despite the drawbacks.

"There's a tension there," he said. "Do I wait for a nuclear medicine study or do I get something going that gives me the quickest ability to assess what's going on with a patient?"

Accessibility Statement

At MedPage Today, we are committed to ensuring that individuals with disabilities can access all of the content offered by MedPage Today through our website and other properties. If you are having trouble accessing www.medpagetoday.com, MedPageToday's mobile apps, please email legal@ziffdavis.com for assistance. Please put "ADA Inquiry" in the subject line of your email.